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Aerial images of fields are useful tools for detecting crop variations and equipment problems that are hard to see from the ground, says Tom Oswald, a Cleghorn, IA, farmer who’s used aerial imagery for several years.

The view from 1,000 ft. up offers “a different perspective,” Oswald says, one that can have an important influence on how growers manage their farms. “I doubt if I have ever seen an aerial photo that hasn’t stimulated me to think deeper about my crop-management strategy. It adds a dimension you likely would not see otherwise. Think of the old saying about how you can’t see the forest for the trees.”

Rosalind Leeck, formerly with the Indiana Agriculture Department, now with the Indiana Soybean Alliance, has worked with a group of Jasper County farmers who are using aerial imagery to evaluate N management. For growers, the sky view often provokes “Aha! moments,” she says. “You can identify things right away that you can’t see with scouting.” Equipment goofs are a good example. Planter row skips, plugged nozzles, center irrigation-pivot stops or slips, herbicide overlaps – “these are things you wouldn’t necessarily see from the roadside or on the yield monitor.”

For instance, uneven N application sticks out like a sore thumb from the air.

Jason Abbring, Wheatfield, IN, had no idea that three knives on his anhydrous ammonia applicator were partially plugged until he saw the evidence on an aerial photo taken in late August. “It was a big surprise. I wouldn’t have known about this without the image. I couldn’t see it on the yield monitor because I applied the anhydrous at an angle to the rows.”

The aerial image of Abbring’s cornfield, taken as part of a pilot program sponsored by the Indiana Department of Agriculture and the Indiana On-Farm Network, showed a distinct pattern light and dark green striping. The lighter green stripes were N-stressed plants, says Dan Perkins, a conservation specialist with the Jasper County Soil and Water Conservation DistrictinRensselaer. Perkinsused GIS tools to zoom in on the photo and measure the distance between the stripes, which correlated to the spacing of Abbring’s anhydrous knives.

Perkins also used the aerial image to collect samples for late-season stalk-nitrate tests, a measure of N sufficiency. “We call it guided stalk-nitrate sampling,” Perkins says. Instead of sampling at random, the geo-referenced photos lead you to a field’s problem areas.

Samples taken from Abbring’s field in 2010 revealed N stress in the partly plugged rows. In addition, the stalk-nitrate tests showed that the entire field “had not had enough N to accommodate a reasonable yield,” Abbring says, due to heavy rains.

As a result of this information, Abbring cleaned and double-checked all the anhydrous knives and added an N stabilizer to his spring preplant N application. “If you don’t know a problem exists, it’s pretty hard to cure it.”